A fast-moving wildfire in southern Oregon expanded Monday, swallowing an unknown number of structures and forcing the evacuation of more than 100 residents.

The fire started at around 2 p.m. local time Sunday in a residential area about an hour's drive to the northeast of Klamath Falls, Oregon. Initially, the fire was just around 75 acres, but swelled Sunday thanks to an abundance of dry timber and brush. As of 1 a.m. local time Monday the fire had grown to more than 4 1/2 square miles, according to the Associated Press.

Some of those flames consumed structures in the area, but because of the intense flames fire crews couldn't reach the affected areas to determine just how many buildings had been compromised.

"What would really help is rain, but there is no rain in sight," Erdman said. "Southwest Oregon is in the heart of its dry season. Only one inch of rain falls, on average, in the entire month of July."

"Unfortunately, the heat will continue, with daytime highs soaring into the mid-90s through Wednesday, with only a slight cool-down later this week."

And so with the fire still growing into the evening hours Sunday, Klamath County sheriff's deputies went door-to-door in the Moccasin Hills subdivision to evacuate more than 100 people along Sprague River Drive and North Arrowhead Lane, KVAL reports.